in my experiences, hd 600/650 are the most forgiving of mp3 and poor recordings. they make even youtube tube songs and 160kbps sound decent. though of course, lossless is ideal whenever possible.

Yes, I have the same experience. I used to have a DT880 but they were ultimately a little too revealing in terms of making low bitrate files and badly mastered pieces sound bad. I like to enjoy the music I am listening to so having a more forgiving can is important to me. The HD650 is great for this reason.